biopsych ao3s

limitation of fight or flight response

only accounts for two responses - GRAY ET AL argues that first response to danger = freeze where humans become hyper-vigilant to decide best course of action

L - suggests that the response is limited and doesn’t fully explain complex cognitive and bio factors

limitation 2 of fight or flight response

not applicable to females - TAYLOR suggests that women adopt a ‘tend and befriend’ response where they protect offspring and form alliances. shows BETA BIAS in this area of psych

L - although the original response is limited, it has prompted more recent research

strength of localisation theory

recent and robust evidence from brain scans - PETERSON ET AL used brain scans to show how wernicke’s area (left temp lobe) was active in listening tasks, and broca’s area (left front lobe) was active in reading tasks. Also, semantic and episodic memories are found in diff parts of prefrontal cortex

L - objective and scientific evidence supports the theory

strength 2 of localisation theory

neurosurgery evidence - DOUGHERTY ET AL studied 44 ppl w/ OCD who had undergone a cingulotomy and found that post 32 weeks, 30% showed a successful response to surgery and 14% showed a partial response

L - behaviours linked to mental disorders may be localised

weakness of localisation theory

lashley’s equipotentiality theory - idea that basic motor and sensory functions are localised but higher mental functions such as learning aren’t.

he removed areas of the cortex (betw. 10-50%) in rats learning a maze route and found no area was more important than any other in terms of its ability to help learn the route.

L - higher cognitive processes aren’t localised but distributed in a more holistic way.

weakness 2 of localisation theory

doesn’t take into account individual differences - HERASTY found that women have larger broca’s and wernicke’s areas than men, which could explain the greater ease of language use amongst women

L - suggests a level of beta bias in theory as differences betw. men and women are ignored

limitation of lateralisation and split-brain research

limited scope for generalisability - split-brain procedures aren’t carried out much in modern healthcare so studies have limited sample sizes. Sperry’s patients were also compared to neurotypical control groups but none of them had epilepsy, so epilepsy could be a CV

L - conclusions may not generalise to the wider population

strength of lateralisation and split-brain research

research supports the idea that both hemispheres process info differently - FINK ET AL used PET scans and found that when non-split brain ppl were asked to attend to global elements of a pic (e.g. whole forest) the right hemisphere was more active, whereas when asked to focus on finer details (e.g. individual trees), the left hem was more active

L - therefore hemispheric lateralisation is a feature of both split and non-split ppl (supporting idea that both hemispheres have distinct functions)

limitation 2 of lateralisation and split-brain research

over-exaggerates/oversimplifies hem lateralisation - the difference between left and right hem is a lot less clear-cut. e.g. language might not be restricted to left hemisphere as TURK ET AL found a patient who suffered damage to the left hemisphere but developed the capacity to speak in the right hem

L - the hem’s flexibility suggests that lateralisation isn’t fixed and is more complex

strength 2 of lateralisation and split-brain research

provides an adaptive function - ROGERS ET AL found that chickens with lateralised brains could find food whilst watching for predators whereas chickens reared in the dark couldn’t as their brains weren’t lateralised

L - therefore there is evidence for the advantages of lateralisation

strength of brain plasticity

it is a life-long ability - BEZZOLA ET AL showed how 40hrs of golf training produced changes in the neural representations of movement in ppts aged 40-60s, using fMRIs to observe the increased motor cortex activity compared to novice golfers

L - this shows that neural plasticity can continue throughout the lifespan

limitation of brain plasticity

may have negative behavioural consequences - MEDINA ET AL found that the brain’s adaptation to prolonged drug use led to poorer cognitive functioning + increased dementia risk

60-80% of amputees have been known to develop phantom limb syndrome due to cortical reorganisation in the somatosensory cortex (RAMACHANDRAN ET AL)

L - this suggest that the brain’s ability to adapt to damage isn’t always beneficiall

limitation 2 of brain plasticity

flawed research - Maguire didn’t test the taxi drivers before they became drivers so clear changes in brain structures cannot be concluded. it could be that they already had larger hippocampus before becoming taxi drivers

L - therefore, as cause and effect can’t be definitively established, further research is needed

strength of functional recovery

practical RWA - contributions to the field of neurorehabilitation e.g. development of constraint-induced movement therapy to help stroke patients use affected body parts

stem cell research could make neuronal transplantation possible

L - therefore it has increased practical value

strength 2 of plasticity and functional recovery

research support - HUBEL AND WIESEL sewed one eye of a kitten shut and analysed the brain’s cortical responses. the area of the. visual cortex associated w/ the shut eye wasn’t idle but continued to process info from the open eye instead

L - this demonstrates how loss of function leads to compensatory activity in the brain, supporting evidence for plasticity and functional recovery

weakness of functional recovery

recovery depends on many factors - SCHNEIDER ET AL found 40% ppts who achieved ‘disability free recovery’ had 16+yrs of education vs. only 10% with 12 yrs of education

TEUBER ET AL found that recovery in brain damaged soldiers was more likely in those under 20yrs old (60% showed significant improvement in movement and visual problems) vs 26yrs (only 20%)

L - Functional plasticity may reduce with age but may increase with a longer period of education

strength of fMRI

doesn’t use radiation - if done correct, it’s risk-free, non-invasive and straightforward to use. produces images w/ high spatial res

L - fMRI can safely provide clear picture of brain activity

weakness of fMRI

expensive compared to other techniques - studies use small samples due to limited availability and funding, reducing generalisability of results. funding contrasts with the poor temporal res, shown through 5-second time-lag of image on the screen

L - delay may not represent real-time brain activity accurately, casting doubt on its precision + highlighting practical + financial challenges

strength of EEG

Shown to be an invaluable diagnostic tool - useful in studying the stages of sleep and diagnosing epilepsy. it has high temporal res and is much cheaper than fMRIs

L - shows real-world usefulness

weakness of EEG

generalised nature of info received - EEG isn’t useful for pinpointing exact source of neural activity and only reasonable accurate. it’s also uncomfortable for ppt with electrodes attached to the head, which could result in an inaccurate reading due to discomfort

L - suggests that researchers will find it hard to distinguish between activities originating in diff but adjacent locations

strength of ERP

produces very specific measurements of neural procewsses - ERP is derived from EEG so has good temporal res as well compared to fMRI

L - ERPs are used frequently to measure cognitive functions + deficits such as allocation of attentional resources + working memory maintenance

weakness of ERP

lack of standardisation in methodology makes it difficult to confirm findings - to establish pure data, background ‘noise’ and EVs must be completely eliminated, which isn’t easy

L - therefore this underscores the complexities associated with ERPs

strength of post-mortem exams

provided the foundation for early understanding of key processes in the brain - Broca and Wernicke both relied on PMEs to establish links betw. language, brain and behaviour decades before neuroimaging. they also allow deeper regions to be investigated compared to non-invasive techniques

L - therefore they are valuable in helping improve medical knowledge and in helping to generate hypotheses for further study

weakness of post-mortem exams

causation is an issue - observed damage to brain may not be linked to deficits under review but other unrelated trauma or decay. this may be a result of studying pure physiology rather than dynamic brain activity as done in fMRIs. they also raise ethical issues of informed consent from the individuals before death

L - this challenges the usefulness of PMEs in psych research

strength of research into circadian rhythms

practical application - there is more info on the negative consequences of shift work as it disrupts the circadian rhythms (desynchronisation). BOIVIN ET AL found that night workers experience reduced concentration at 6am where mistakes are more likely to happen. KNUTSSON found that shift workers = 3x more likely to develop heart disease

L - research has real economic implications in terms of how to best manage work productivity

strength two of research into circadian rhythms

drug tratment practical application - research led to the field of chrono-therapeutics. BONTEN ET AL foubnd that aspirin as a heart attack treatment is the most effective when taken at night as heart attacks are likely to happen in the morning so timing matters.

L - research can increase the effectiveness of medical treatments

weakness of research into circadian rhythms

individual differences - CZEISLER ET AL found that individual sleep-wake cycles can vary from 13-65hrs. DUFFY ET AL found that some prefer sleeping early and waking early whereas others prefer the opposite. when Siffre did his study again at 60, his internal clock had slowed

L - generalisations are difficult to make as idiographic case studies are based on small samples that might not represent individual differences

weakness 2 of research into circadian rhythms

poor control in research done - ppts in study were deprived of natural light but still had artificial light, e.g. Siffre turned on a lamp which stayed on till he slept. however, CZEISLER ET AL were able to adjust ppt’s rhythms from 22 to 28hrs using dim lighting

L - researchers had ignored an important CV in circadian rhythms

weakness of using animals for research of endogenous pacemakers

ethical issues - in DECOURSEY’s study, the chipmunks were put at significant risk when they had their sleep-wake cycles altered and left vulnerable to be killed by predators

L - researchers should find ways to investigate the effects of EPs that don’t endanger the animals studied

weakness 2 of research into endogenous pacemakers

they can’t be studied in isolation - total isolation studies are extremely rare. in everyday life, pacemakers and zeitgeibers intaract and it may make little sense to separate to two for the purpose of research.

L - this suggests the more researchers attempt to isolate the influence of internal pacemakers, the lower the validity of the research as they work in an interactionist system.

weakness of research into exogenous zeitgeibers

evidence challenges the role - MILES ET AL recount the study of a man who had an abnormal circadian rhythm of 24.9hrs. despite social cue exposures, it couldn’t be adjusted so he had to take sedatives to keep the 24hr pace.

L - social cues alone aren’t effective in resetting the rhythm so the role of EZs might be overstated

weakness 2 of research into exogenous zeitgeibers

they don’t have the same effect in all environments - ppl who live in the arctic circle have similar sleep patterns all-year round despite spending around six months in total darkness.

L - the sleep/wake cycle is primarily controlled by endogenous pacemakers that can override environmental changes

strength of research into exogenous zeitgeibers

practical applications - research has been used in the management of insomnia among the elderly. HOOD ET AL have highlighted the role that exo zeitgeibers play in sleep patterns and found that increased physical activity and exposure to natural light significantly improved their insomnia. BURGESS ET AL found that exposure to bright light prior to a east-west flight decreased the time needed to readjust to local time on arrival

L - this shows how knowledge can be used to help entrain and synchronise our bio rhythms more effectively

strength of research into infradian rhythms

can be used to regulate behaviour - PENTOL-VOLK ET AL found that women preferred feminine faces at the least fertile stage of their menstrual cycle, but more masculine faces at their most fertile point

L - these indicate that women’s sexual behaviour is motivated by their infradian rhythms, highlighting the importance of studying them before drawing conclusions about social behaviours

weakness of research into infradian rhythms

the endogenous systems are heavily influenced by external cues - MCCLINTOCK AND STERN’S study showed how pheromones could act as exogenous factors to synchronise menstrual cycles amongst women. 68% of 29 women experienced changes to their menstrual cycle bringing them closer to their ‘odour donor’ - stress, diet and exercise also affect the menstrual cycle

L - the timing of menstrual cycles isn’t only governed by internal effects

C/A - menstrual synchrony shows evolutionary value - it might have been an advantage to be pregnant at the same time as if babies lost their mothers, they could still be breastfed, therefore increasing survival chances

L - this strengthens the view that menstrual synchrony goes beyond curiosity and gives insight into how behaviour was adapted for survival

strength 2 of research into infradian rhythms

RS for role of melatonin in SAD - TERMAN found that SAD is more common in Northen countries where winter nights = longer e.g. 10% of ppl living in New Hampshire are affected w SAD vs. 2% in southern Florida

L - these results suggest that SAD is affected by light that results in higher melatonin levels

weakness 2 of research into infradian rhythms

the effectiveness of interventions - 80% of interventions are successful and the therapy to help ppl w SAD is safe however there are long-term drawbacks such as discomfort (headaches/eye strain). ROHAN ET AL suggests a relapse rate of 46% over successive winters, surpassing a comparison group using CBT at 27%

L - the drawbacks prompt questions about the adequacy of research in these rhythms, given the uncertain long-term efficacy fo treatments

strength of research into ultradian rhythms

high levels of objectivity and control over EVs - sleep research = in labs so less temporary variables (noise/temp), and data is collected quantitatively so can be analysed statistically

L - internal validity is high so we can be more confident when establishing cause and effect

C/A - ppts must be subjected to a specific level of control and attached to monitors that measure rhythms which could be uncomfortable, leading to falsely represented sleep cycles, so it’s hard to investigate ultradian rhythms due to the risk of false conclusions

strength 2 of research into ultradian rhythms

practical value - improved understanding of age-related changes in sleep. SWS reduces w age, and growth hormone produced at this time, so it is reduced in older people. VAN CAUTER ET AL found that sleep deficit could result in various issues in old-age such as reduced alertness

KLEITMAN suggested a basic rest-activity cycle (BRAC) → period of alertness followed by a period of physiological fatigue. ERICSSON ET AL found that best violinists practiced for 3 sessions during the course of the day no more than 90mins w/ break in betw. to ‘recharge’

L - highlights the usefulness of the research

weakness of research into ultradian rhythms

individual differences - TUCKER ET AL found differences betw. ppts in terms of the duration of each stage, particularly stage 3 and 4. despite study = in lab w controlled CVs/EVs, there were differences (biological differences, not situational factors)

L - a range of factors contribute to ultradian rhythms